The Laboratory of Pathology (LP) conducts a fully ACGME accredited AP3 program for residents in Anatomic Pathology at the National Institutes of Health. A fourth year of training is fully funded at which time the residents may participate in electives or research. Residents gain a rich and diversified exposure to the practice of anatomic pathology. They gain diagnostic expertise on material from patients enrolled in protocols conducted by 26 institutes and centers, supporting over 3,000 recruiting studies, involving a wide diversity of research in areas such as oncology, infectious disease, digestive and kidney diseases, general medicine, neurological disorders, cirrhosis, etc. In addition, the LP receives more than 3,000 extramural consultation cases each year. The philosophy of the training program is to provide broad and in-depth exposure to the subject matter of anatomic pathology, with an emphasis on clinical correlation, relationships to disease mechanisms, and exposure to investigational opportunities. The staff conducts an integrated residency-teaching program in which case material is incorporated with didactic sessions to explore all aspects of Anatomic Pathology. Because our clinical programs are integrated with the research activities of the NIH, our residents are exposed to information regarding the pathogenesis and pathophysiology of diseases that they are learning to diagnose on a regular basis. This insight into the basic disease mechanisms of pathology enhances their educational experience. The Laboratory of Pathology conducts all of the diagnostic anatomic pathology for all the patients undergoing clinical trials in the Clinical Center, for all patients being considered for entry into clinical trials, and for epidemiological and case studies of disease pathophysiology. The Laboratory conducts 6,000 surgical pathology studies, 100 autopsies, 2,000 special diagnostic studies, 3,500 cytopathology studies, and 450 flow cytometry studies per year. Several thousand-consult cases are received in the Laboratory of Pathology for expert consultation in the fields of hematopathology, OB/GYN pathology, cytopathology, and pediatric pathology. Clinical cytogenetic studies include classical G-banded karyotyping, as well as FISH, SKY, and CGH analyses.